Hello,

Solution for your question is:

Distance ( Height) = 70 m

Speed  = 25 m/s

Time = Distance/ speed

Time = 70/25

= 2.8 s

Speed= Distance/ Time

Speed = 1000 / 2.8

=357.14 m/s

So the speed of the object when it falls from the height of 1000 m is 357.14 m/s

Hope it helps

Feel free to ask any questions if you have